Spray tank



FIG. 1 is a perspective view of a new and ornamental design for a spray tank, with elements shown in phantom for environment only and forming no part of the claimed design;

FIG. 2 is a front elevation view thereof

FIG. 3 is a rear elevation view hereof

FIG. 4 is a first side elevation view thereof

FIG. 5 is a second side elevation view thereof

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

CLAIM The ornamental design for a spray tank, as shown and described. 